The invention relates to a chuck for screwdriver inserts, having an insertion cavity of a bush, the insertion cavity being adapted in cross section to the polygonal section of the insertion shank of the bit, windows opposite one another in the corner region of the insertion cavity being located in the bush, and round clamping bodies lying in said windows on supporting shoulders, the diameter of which clamping bodies is greater than the window wall thickness and which are loaded inward toward the cavity by an inclined surface of a spring-loaded actuating sleeve and press in point contact against the corner of a corner recess of the insertion shank.
In such known chucks on the market, the bush has round clamping bodies in opposite windows in the corner region of the insertion cavity, the clamping bodies being arranged in the same cross-sectional plane. These clamping bodies act jointly on the corner recesses of the insertion shank.